Re: [LAU] Sequencer suggestions?

On Tue, 2014-08-26 at 14:08 +0000, Fons Adriaensen wrote:
> On Tue, Aug 26, 2014 at 03:46:59PM +0200, Ralf Mardorf wrote:
>
> > > "2.23 DC Offset Remover (dcRemove, 1207)
> > >
> > > Simply removes the DC (0 Hz) component from an audio signal, uses a high
> > > pass filter, so has some side effects, but they should be minimal." -
> > > http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#tth_sEc2.23
> > >
> > > Would this protect against phasex loudspeaker-heater feature?
> >
> > It's said it's not audible, IIRC I sometimes heard a loud, very loud
> > single crackle. Could this be caused by a dc offset?
>
> Yes. The problem here is that the DC offset originates in the
> oscillators and is multiplied by the envelope. Hence the result
> is not really constant. A highpass filter will remove the constant
> or slowly changing part during a note, but not the 'thumps' at the
> beginning and end. Depending on the cutoff frequency and the rise
> and fall times of the envelope these could still be much larger than
> the signal. They won't probably fry you speaker but could result in
> clipping and hence crackles.
>
> The only real solution is to remove the DC offset at the output
> of the oscillators, before it enters the rest of the audio chain.

Thank you Fons,

I reported the issue.

https://github.com/williamweston/phasex/issues/10#issue-41179099

I've got no doubts anymore, that I experienced the DC offsets too.

Regards,
Ralf

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Received on Tue Aug 26 20:15:03 2014